REPRODUCTIVE PROBLEMS OF REPTILES
Paul Raiti, D. V.M. *
Beverlie Animal Hospital
17 West Grand S'treet
Mount ~"e·rnon. New York 10552
US:4
Male snakes and lizards possess paired copulatory organs called hemipenes that are located in the
tail immediately caudal to the vent. The hemipenes are inverted and attached to the ventral
processes ofthe coccygeal vertebrae by retractor muscles. Sexing in male snakes is performed by
inserting appropriately sized probes into the hemipenal pockets. Male snakes usually probe 12-16
subcaudal scales. Female snakes, lacking hemipenal pockets, probe 2-6 subcaudal scales. Boas and
pythons are sexually dimorphic~ males possess cloacal spurs which are utilized during copulation.
Females either lack these structures or they are reduced in size. In those species of lizards in which
sexual dimorphism is not apparent, such as bearded dragons (Pogolla vitticeps) and monkey-tailed
skinks (Corucia zebrata), sexing can be performed under sedation. Ketamine hydrochloride
(Ketaset, Bristol-Meyers, Fort Dodge, Iowa) is administered at 20 mg/kg i.m. followed by masking
with isoflurane (Aerane, Anaquest, Madison, Wisconsin) at 2-3%. Digital pressure is applied to the
base of the hemipenal pocket causing temporary prolapse of the organ. Male chelonians and
crocodilians possess single copulatory organs which are located on the floor of the cloaca.
In snakes and lizards the hemipenes can become clogged with inspissated semen and desquamated
epithelial cells. This condition occurs during breeding season. It is associated with premature
ejaculation or repeated copulatory attempts with a female that is not receptive. The vent appears
swollen and painful. Upon retraction ofthe first caudal scale the hardened tip of the hemipenal plug
becomes visible. It is grasped with blunt forceps or hemostats and pulled cranially while pushing
on the base of the hemipenal bulge. An antibiotic cream such as silver sulfadiazine (Silvadene
Cream 1%, Marion Labs, Kansas City, Missouri) is then applied to the vent.
Prolapsed male copulatory organs (paraphimosis) are also seen more frequently during breeding
seasons. Chelonians and snakes are most commonly affected. This condition is associated with
trauma during copulation (ifthe male is dragged by the female). In chelonians it can also occur due
to bite wounds. Substrate adhering to the prolapsed organ coupled with desiccation prevents
retraction of the affected organ. Initial therapy should be directed toward reducing cellulitis and
controlling secondary infection. This is accomplished by immersion in a hypertonic solution and
administering topical antibiotics such as 1% silver sulfadiazine. In chelonians it is easy to reposition
the prolapsed penis due to the markedly distensible cloaca. After the organ has been repositioned
under anesthesia (ketamine and isoflurane), one or more purse string sutures are placed around the
vent. Sutures are removed in approximately 4 wk. In snakes and lizards it is more difficult to
replace the prolapsed hemipene into the hemipenal pocket. Sometimes blood may be aspirated from
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the engorged venous sinus causing a reduction in size of the organ. After the hemipene is replaced
into its respective pocket a purse string suture is placed in the cloaca to prevent subsequent
prolapse. Ifthe hemipene is necrotic than amputation is performed. Polydioxanone mattress sutures
(pDS, Ethicon, Somerville, New Jersey) are placed in the base of the organ to prevent hemorrhage.
Amputation is performed approximately 3 mm distal to the sutures.
Dystocia has been reported to occur in approximately 9% of captive reptiles. It develops
secondarily to a variety of circumstances such as unsuitable substrate availability, morphologic
abnormalities (excessively large eggs, dead fetuses, uterine obstruction/compression), and uterine
infections. Clinical signs are variable. Egg bound reptiles may appear restless in an effort to locate
suitable nesting sites. Sometimes there is a cloacal discharge. In chelonians paresis may be observed
due to pressure on the obturator nerves from an egg(s) lodged in the pelvic canal. Eventually the
egg bound reptile becomes depressed and dehydrated. Diagnosis in long term captives is greatly
aided when presented with an accurate history. Knowledge of observed breeding dates and normal
gestation period for that particular genus aids in determining anticipated ovipositing dates. For
example, gestation for most temperate colubrids is from the last copulation until 10-14 days after
the next shed (pre-egglaying shed). During gestation the gravid snake normally refuses food and
should have access to a warm spot of 30°C (85°F). In wild caught specimens one must rely on
natural reproductive data (if available), physical examination, and specific diagnostic tools. This can
be complicated by the fact that many female reptiles can store spetm in oviductal seminal receptacles
for years prior to fertilization. The decision for veterinary intervention should be based upon several
factors. If gestation time is significantly longer than normal for the taxon involved and the reptile
is debilitated then prompt therapy is indicated. Hematology and plasma biochemistries can eliminate
common complications such as hypocalcemia and renal disease. Radiography, in addition to
confirming gravidity or pregnancy, can also identify abnormalities such as metabolic bone disease
and fused, fractured, or excessively large eggs. In the green iguana (Igual1a iguana), which is
commonly presented for anorexia associated with reproductive problems, dystocia has been divided
into two phases, pre-ovulatory follicular retention and postovulatory egg retention.
In the former condition the follicles have radiographically indistinct borders and tend to be located
more cranially in the coelomic cavity. Plasma calcium and phosphorus values are markedly elevated
during this time. Resorption of these follicles normally occurs over a period of approximately 3
wk. Postovulatory eggs are characterized radiographically by more distinct borders and occupy the
entire coelomic cavity. In chelonians, fractured eggs may be caused by sexually aggressive males.
Excessive circumferential calcareous lamellae indicate prolonged egg retention. Correcting
dehydration and maintaining the reptile within its preferred optimal temperature zone (POIZ) are
of paramount importance before the administration of therapeutics. Dehydrated reptiles soaked in
balanced electrolyte solutions commonly gain up to 25% of their body weight.
Unless surgical intervention is clearly indicated, medical therapy or changes in husbandry should be
attempted to stimulate oviposition. For example, it is known that gestation in the iguana is
approximately 50-60 days. If a healthy iguana diagnosed with postovulatory egg retention has not
been provided with a suitable nesting site then recommended husbandry modifications may be
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appropriate. Substrate composed of sand and potting soil at a 1: 1 ratio? placed in a horizontal plastic
container 4 ft long, provides a suitable ovipositing chamber. Vasotocin is the naturally occurring
reproductive neuropeptide found in reptiles; hence, oxytocin is not as effective in inducing uterine
contractions. At this time, however, oxytocin is the only available hormone in its class that is
available to veterinarians. Chelonians respond better than snakes and lizards to oxytocin; in fact?
oviposition usually occurs within 1 hr after administration of oxytocin (Oxytocin, Phoenix
Pharmaceutical, St. Joseph, Missouri) at IOU/kg i.m. b.i.d. for 48 hr. Oxytocin seems to work
more effectively when administered at a higher dose (2 U/IOO g i.m. b.i.d. for 2-3 days) in snakes
and lizards. Concurrent treatment with calcium (Calphosan? Glenwood Inc.? Tenafly, New Jersey)
at 0.5 ml/kg i.m. is controversial. In the author's experience calcium does not appear to enhance
uterine contractions in reptiles unless hypocalcemia is present. Treated patients should be placed
in a warm secluded environment at 30-36°C (85-90°F). In snakes, if there is no response by 48 hr,
ovacentesis of the most distal egg is performed. Sedation is usually not required. A 22 ga needle
attached to a 10 mI. syringe is used. After swabbing the skin with alcohol and betadine solution the
needle is inserted at the junction ofthe lateral and ventral scales. The average colubrid egg contains
10 ml of content. By decompressing the egg, and repeating oxytocin, the chances of induced
oviposition are dramatically increased. Subsequently, the collapsed egg commonly passes within
24 hr. Ifthe decompressed egg does not pass, then sedation with ketamine and isoflurane anesthesia
is performed. Utilizing a vaginal speculum the cloaca is dilated and the collapsed egg is grasped
with towel forceps. Ifthere are oviductal adhesions further manipulation should immediately cease
and salpingotomy performed.
The technique for celiotomy/salpingotomy has been well described. After induction with ketamine
and atropine (atropine sulfate, Phoenix Pharmaceutical, St. Joseph, Missouri) at 0.02 mg/kg i.m.)
intubation is performed. In reptiles the glottis is open only during active respiration. Isoflurane is
the anesthetic of choice and maintenance is achieved at 2-3% with oxygen flow at IL/min. Reptiles
lack a counterpart ofthe mammalian diaphragm and so positive pressure ventilation at 5 breaths/min
is employed during anesthesia. Heating pads set at 28°C (82°F) are also recommended. The
surgical site is aseptically prepared with alcohol and betadine solution. In snakes, an incision for
celiotomy is made at the junction of the ventral and first row of lateral scutes. This surgical
approach avoids the large abdominal vein and prevents the incision from coming in direct contact
with the substrate postsurgically. Beneath the skin lies the abdominal muscle layer and peritoneum
which are incised. Sometimes multiple incisions have to be made in snakes that have more than one
retained egg. After the egg(s) has been removed the oviduct is closed with an inverting pattern if
possible. Many times the oviduct is attenuated permitting only simple interrupted sutures. Reptiles
do not possess lysozymes; accordingly, suture material that is degraded by hydrolysis rather than
phagocytosis (polydioxanone) should be used. Skin closure is done in an everting pattern. In
lizards a paramedian incision is recommended. This avoids the abdominal vein; once visualized it
is retracted laterally. Ovariectomy is recommended for pre-ovulatory follicle retention in iguanas
(assuming there is no anticipated breeding plans). Frequently? these follicles never undergo
resorption causing high mortality rates due to accompanying anorexia. Ovariectomy is easier to
perform during folliculogenesis when the follicles are enlarged because the stretched mesovarium
permits exteriorization ofthe ovaries and better visualization of the vasculature. The right and left
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ovaries lie adjacent to the vena cava and adrenal gland respectively. The oviducts do not have to
be removed during the procedure. With postovulatory egg retention an ovariohysterectomy is
recommended. If the ovaries are left in the coelomic cavity future ovulations may deposit ova in
the coelomic cavity leading to egg yolk peritonitis. Due to the thin abdominal musculature an
everting single layer closure is performed using nylon. Prophylactic antibiotics are administered for
1 wk postoperatively due to the difficulty of sterilizing the skin.
Uterine (distal oviductal) prolapse occurs nlore commonly in chelonians than other reptiles. It may
be associated with dystocia or any condition that causes tenesmus such as parasitism or obstipation.
If the affected tissue cannot be replaced through the cloaca then celiotomy is performed. This
procedure presents a unique challenge in chelonians due to the plastron. In some species that have
a reduced plastron such as the common snapping turtle «(-'heIJ'dra ser/Jel1til1a), access to the
abdomen is accomplished through either inguinal pocket. In most cases however a "trap door" with
a hinge on one side is created using an orthopedic drill or Dremel motor kit. One side is left
attached to the plastron to preserve the vascular supply to the flap. The exact location of the
osteotomy is based upon radiographic findings~ however, most incisions are made in the abdominal
and femoral scutes. The pelvic bones and muscles should be avoided. Immediately beneath the
abdominal musculature and peritoneum are two large venous sinuses that can be retracted.
Salpingotomy and/or ovariohysterectomy is then performed as described above. When concurrent
infection is suspected microbiological cultures should be done. Closure of the plastral flap is done
using sterilized fiberglass and epoxy. Care must be taken to avoid getting epoxy in the
circumferential defect as this may lead to delayed healing. Flunixin meglulnine (Banamine solution,
Schering-Plough, Union, New Jersey) administered at 1.5 mg/kg i.m. s.i.d. for 2 days appears to
diminish postsurgical discomfort and initiate an earlier return of appetite.
Infectious salpingitis is associated with ascending infections from the cloaca. Pseudomonas spp.
was isolated from bilaterally infected oviducts in a pregnant Solomon Island ground boa (Cal1doia
carinata paulsol1i) which delivered stillborn young. Parasitic salpingitis (Mol10CerC()monas spp.)
causing fetal deaths has been reported in a boa constrictor.
Oophoritis may be aseptic or infectious. Aseptic inflammation of the ovaries has been reported in
geriatric turtles while follicular resorption was occurring. Trauma can cause follicular rupture
producing severe egg yolk coelonlitis. Bacterial infections and ovarian cysts have also been
reported. Pseudomonads, coliforms, and salmonellae are some examples of bacterial isolates from
infected ovaries. Diseased ovaries can become enlarged enough to cause visible distension of the
abdomen. Treatment requires celiotomy, ovariectomy, abdominal lavage with dilute betadine
solution, and treatment with appropriate bacteriocidal antibiotics based upon ~ulture and sensitivity
results.
Aggression in sexually mature iguanas has been well documented. This occurs during breeding
season, however some specimens are aggressive throughout the year. Castration is currently being
perrormed on a limited basis~ long term results have yet to be documented. The testicles are located
in the same location as the ovaries and the technique is similar to ovariectomy. Better results have
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been preliminarily reported when castration is performed prior to sexual maturity when the iguana
has a snout to vent length of approximately 12 in. Territoriality is diminished in conjunction with
development of the secondary sexual characteristics. Some veterinarians are now routinely
recommending spaying and castration in all iguanas that not intended for breeding purposes.
REFERENCES
Barten, S.L. 1993. The Medical Care of Iguanas and Other Common Pet Lizards. Exotic Pet
Medicine I. Veterinary Clinics of North America. 23(6).
Bennett, RA. 1991. Reptilian Surgery Part II. Management of Surgical Diseases.. Exotic Animal
Medicine in Practice, Veterinary Learning Systems, Trenton, New Jersey. Volume 2.
Beynon, P., M.e. Lawton, and J. Cooper. 1992. Manual of Reptiles. BSAVA, Iowa State
University Press"
Frye, F.L. 1991. Biomedical and Surgical Aspects of Captive Reptilian Husbandry. Krieger
Publishing, Florida.
Lloyd, M. 1991. Reptile Dystocia: Management Strategies., Treatments and Relative Success
Rates of the Synthetic Hormone Vasotocin. German Veterinary Association, Fourth International
Colloquium on Pathology and Medicine of Reptiles and Amphibians.
Mader D"R. 1995. Personal Communication.
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